title: Narrow band UV emission from direct bandgap Si nanoclusters embedded in bulk Si.
abstract: We report on the formation of UV emitting Si nanoclusters (NCs) in Si, using a two stage Au implantation technique. These Si NCs, with an average size of 2 nm, show photoluminescence at room temperature, over a narrow band of about 100 meV with a peak of emission near 3.3 eV. With emission lifetimes in the range of 1.5-2.5 ns, the transitions seem to come from excitonic recombinations across a quasi-direct gap. Since the structures are below the surface, there is no adverse effect of oxidation resulting in a shift in emission wavelength. On the other hand, an annealing at 500 °C has been found to result in a significant increase in the emission intensity. This is due to localized plasmon induced electric field enhancement in Au nano-islands in the vicinity.
authors.affiliation: Institute of Physics, Sachivalaya Marg, Bhubaneswar-751005, India.
authors.forename: G
authors.initials: G
authors.lastname: Sahu
authors.forename: H P
authors.initials: HP
authors.lastname: Lenka
authors.forename: D P
authors.initials: DP
authors.lastname: Mahapatra
authors.forename: B
authors.initials: B
authors.lastname: Rout
authors.forename: F D
authors.initials: FD
authors.lastname: McDaniel
mesh_terms: D006046:Gold / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology; D010316:Particle Size; D012825:Silicon / Q000737:chemistry*; D013499:Surface Properties; D014466:Ultraviolet Rays
chemical_list: D006046:Gold; D012825:Silicon